In recent years, there has been a considerable increase in the use of lasers in medicine and surgery. In one class of medical lasers, the laser energy is delivered from the laser to the patient via an optical fiber. Once such laser system which has achieved significant commercial success is marketed by the assignee herein under the trademark Versapulse. The Versapulse system includes a solid state Holmium:YAG laser that generates an output of 30 watts average power at a wavelength of 2.1 microns. The laser energy is coupled through an optical fiber which terminates in a handpiece manipulated by the surgeon.
A laser system of this type is used for a wide variety of surgical applications and is particularly suited for arthroscopic procedures. As the field has grown, a variety of handpieces have been developed which allow the surgeon latitude in treatment approaches. For example, the delivery end of the tip projecting out of the handpiece can be straight or curved. The delivery end of the probe can also include tines to help capture and stabilize cartilage during ablation. At the present time, a surgeon will often desire to use more than one probe configuration during a single procedure.
As can be appreciated, because of the potential for spreading infection, a probe used during one procedure can not be used with another patient in a subsequent procedure unless some form of sterilization was performed. Unfortunately, the probes that were initially introduced to the marketplace were not designed to withstand sterilization procedures and were therefore discarded after a single use.
Since that time, attention has been given to improving the design of the probe so that it can be sterilized. Within the last year, the assignee herein has manufactured and sold probes which could be sterilized using gas techniques. Unfortunately, gas sterilization is a relative time consuming, costly and potentially carcinogenic approach. In contrast, high temperature steam sterilization in an autoclave is faster, safer and less expensive. However, the prior probes were incapable of withstanding the high temperatures encountered in an autoclave. Accordingly, it would be desirable to provide a probe which could be sterilized in an autoclave.
The problems associated with sterilizing probes have been compounded by the proliferation of various tip designs described above. As can be appreciated, if a surgeon desires to use two or three different probes with different tip designs in a single procedure, all of the probes would have to be sterilized after use.
One prior art approach which has been implemented to address this difficulty has been to provide a two-part probe. The two-part probe includes a disposable tip piece and a reusable handpiece. During any given procedure, the surgeon can use a single handpiece and change tips (and delivery modalities) depending upon the requirements of the procedure as it progresses. At the end of the procedure, all of the tips that were used are discarded. Only the single handpiece needs to be sterilized.
There are still some difficulties associated with the latter approach which utilizes a two-part probe. First, the handpiece cannot be sterilized in an autoclave and the less desirable gas sterilization must be used. More significantly, since the delivery fiber now consists of two pieces, a means must be provided to insure that the optical coupling between the abutting ends of the fibers is maintained during use. In the prior art system, the disposable tip included a short extension member which projected about one half inch into the handpiece. A threaded coupling secured the tip in place.
The latter approach can provide good optical coupling when the two parts are initially connected. However, during a surgical procedure, the surgeon will push and twist the probe creating a torque on the interconnection between the tip and the handpiece. More specifically, a surgeon will can exert up to about one pound of force on the end of the tip during a procedure. The amount of torque this force generates is dependent on the length of the tip. Since a standard tip is on the order of five inches in length, the torque at the front end of the handpiece would be five inch-pounds.
When this amount of torque is applied to the optical coupling it can cause the ends of the abutting fibers to become misaligned. When the ends of the fibers become misaligned, the energy of the laser will not be coupled from one to the other but rather will scatter within the handpiece. If the leakage is severe, the fiber and/or the handpiece can overheat and be catastrophically destroyed. Even if the leakage is insufficient to cause destruction, the power lost will prevent the desired laser energy level from being delivered to the surgical site.
Accordingly, it would be desirable and is an object of the present invention to design a optical probe which includes a connectable tip having a configuration designed to maintain optical coupling efficiency during a surgical procedure.
It is a further object of the subject invention to provide a handpiece which can be readily sterilized in a steam autoclave.
It is still another object of the subject invention to provide a tip which is either disposable or could be sterilized in a steam autoclave.